Light water nuclear fission reactors employ neutron absorbing materials to control the reactivity within the reactor core. The temperature within the reactor core may increase due to a loss of coolant flow. The coolant flow may be provided by a pump, and the loss of coolant flow may occur due to a pump shutting down (e.g., due to a loss of power thereto, due to mechanical failure, etc.). A loss of pump flow may be difficult for the nuclear reactor to control without component damage. Reactor designs that rely on the temperature increase of the coolant (i.e., a thermal feedback, etc.) to insert negative reactivity may be subject to a significant time delay between the temperature increase and the corresponding negative reactivity response.